1 from ctypes.util import find_library

     2 from django.conf import settings

     3 

     4 from django.core.exceptions import ImproperlyConfigured

     5 from django.db.backends.sqlite3.base import *

     6 from django.db.backends.sqlite3.base import DatabaseWrapper as SqliteDatabaseWrapper, \

     7     _sqlite_extract, _sqlite_date_trunc, _sqlite_regexp

     8 from django.contrib.gis.db.backends.spatialite.client import SpatiaLiteClient

     9 from django.contrib.gis.db.backends.spatialite.creation import SpatiaLiteCreation

    10 from django.contrib.gis.db.backends.spatialite.introspection import SpatiaLiteIntrospection

    11 from django.contrib.gis.db.backends.spatialite.operations import SpatiaLiteOperations

    12 

    13 class DatabaseWrapper(SqliteDatabaseWrapper):

    14     def __init__(self, *args, **kwargs):

    15         # Before we get too far, make sure pysqlite 2.5+ is installed.

    16         if Database.version_info < (2, 5, 0):

    17             raise ImproperlyConfigured('Only versions of pysqlite 2.5+ are '

    18                                        'compatible with SpatiaLite and GeoDjango.')

    19 

    20         # Trying to find the location of the SpatiaLite library.

    21         # Here we are figuring out the path to the SpatiaLite library

    22         # (`libspatialite`). If it's not in the system library path (e.g., it

    23         # cannot be found by `ctypes.util.find_library`), then it may be set

    24         # manually in the settings via the `SPATIALITE_LIBRARY_PATH` setting.

    25         self.spatialite_lib = getattr(settings, 'SPATIALITE_LIBRARY_PATH',

    26                                       find_library('spatialite'))

    27         if not self.spatialite_lib:

    28             raise ImproperlyConfigured('Unable to locate the SpatiaLite library. '

    29                                        'Make sure it is in your library path, or set '

    30                                        'SPATIALITE_LIBRARY_PATH in your settings.'

    31                                        )

    32         super(DatabaseWrapper, self).__init__(*args, **kwargs)

    33         self.ops = SpatiaLiteOperations(self)

    34         self.client = SpatiaLiteClient(self)

    35         self.creation = SpatiaLiteCreation(self)

    36         self.introspection = SpatiaLiteIntrospection(self)

    37 

    38     def _cursor(self):

    39         if self.connection is None:

    40             ## The following is the same as in django.db.backends.sqlite3.base ##

    41             settings_dict = self.settings_dict

    42             if not settings_dict['NAME']:

    43                 raise ImproperlyConfigured("Please fill out the database NAME in the settings module before using the database.")

    44             kwargs = {

    45                 'database': settings_dict['NAME'],

    46                 'detect_types': Database.PARSE_DECLTYPES | Database.PARSE_COLNAMES,

    47             }

    48             kwargs.update(settings_dict['OPTIONS'])

    49             self.connection = Database.connect(**kwargs)

    50             # Register extract, date_trunc, and regexp functions.

    51             self.connection.create_function("django_extract", 2, _sqlite_extract)

    52             self.connection.create_function("django_date_trunc", 2, _sqlite_date_trunc)

    53             self.connection.create_function("regexp", 2, _sqlite_regexp)

    54             connection_created.send(sender=self.__class__)

    55 

    56             ## From here on, customized for GeoDjango ##

    57 

    58             # Enabling extension loading on the SQLite connection.

    59             try:

    60                 self.connection.enable_load_extension(True)

    61             except AttributeError:

    62                 raise ImproperlyConfigured('The pysqlite library does not support C extension loading. '

    63                                            'Both SQLite and pysqlite must be configured to allow '

    64                                            'the loading of extensions to use SpatiaLite.'

    65                                            )

    66 

    67             # Loading the SpatiaLite library extension on the connection, and returning

    68             # the created cursor.

    69             cur = self.connection.cursor(factory=SQLiteCursorWrapper)

    70             try:

    71                 cur.execute("SELECT load_extension(%s)", (self.spatialite_lib,))

    72             except Exception, msg:

    73                 raise ImproperlyConfigured('Unable to load the SpatiaLite library extension '

    74                                            '"%s" because: %s' % (self.spatialite_lib, msg))

    75             return cur

    76         else:

    77             return self.connection.cursor(factory=SQLiteCursorWrapper)